1. Field of the Invention
The present invention relates to a monitor, and more particularly, to an apparatus for processing image signals in a monitor system having an LCD module.
2. Background of the Related Art
In general, a monitor is a device for displaying image signals received from a PC video card after performing appropriate signal processes such as digital sampling and/or scaling on the image signals. The monitor technology has started from a small CRT (Cathode Ray Tube) monitor, and now a digital displaying technique using an LCD, which is a representative flat display device being adequate for a large monitor, is widely being used. Additionally, the quality of a monitor is often expressed as its resolution rate: i.e., SVGA (800 by 600), XGA (1280 by 768), and SXGA (1280 by 1024).
Reference will now be made in detail to a related art monitor system. FIG. 1 illustrates a typical monitor system according to the related art. According to FIG. 1, the monitor system includes a microprocessor 1 for determining an image mode based on a horizontal and vertical sync signal received and for generating a corresponding control signal to perform appropriate signal processes based on the determined image mode; and a PLL (Phase Locked Loop) 2 for generating a clock pulse based on the control signal generated in the microprocessor 1.
The apparatus further includes an A/D converter 3 for converting the analog R/G/B input image signal into digital signal by sampling based on the clock pulse generated in the PLL 2; a scaler 4 for adjusting the frame sizes of the digital R/G/B image signal based on the control signal of the microprocessor using the clock pulse generated in the PLL 2; a frame buffer 5 memory for storing the output from the scaler 4; an LCD module 7 for displaying the output from the scaler 4; and an OSD generator 6 for generating a corresponding OSD message according to the control signal of the microprocessor 1 when the resolution rate is not in the allowed range set by the LCD module 7.
The procedural steps explaining how the monitor system shown in FIG. 1 works are as follows. First of all, when the analog R/G/B input image signal and the horizontal/vertical sync signals are inputted from the Video card to the A/D converter 3 and to the microprocessor 1, the microprocessor 1 determines the resolution rate (SVGA/XGA/SXVGA) of the inputted image signal using the horizontal/vertical sync signal. Subsequently, the microprocessor 1 provides a corresponding control signal to the PLL 2 for setting up a sampling clock of the A/D converter 3 in order to have a digital conversion corresponding to a desired resolution rate set by a user if the resolution rate of the input image signal is less than or equal to the rate supported by the monitor (For example, the monitor is XGA, and the input signal is XGA or SVGA).
Therefore, the A/D converter 3 simultaneously outputs an 8-bit R/G/B image signal and a dot clock for signal recognition of the scaler 4 by performing an appropriate digital sampling process for which a 95 MHz-sampling clock matching to the horizontal sync signal is generated according to the control signal of the microprocessor 1.
Thereafter, in accordance with the control signal, the scaler 4 stores the output of the A/D converter 3 in the frame buffer memory 5 in frame units being adequate for the XGA resolution rate and outputs it to the LCD module 7 afterward Thereafter, the LCD module 7 reads the 8-bits digital image data generated from the scaler 4 in accordance to the data enable (D/E) signal and the outside clock (OUT CLK) and display them in accordance to the horizontal/vertical sync signal.
On the other hand, in a case where the resolution of the monitor and the input image signal are XGA and SXGA, respectively, a 135 MHz sampling clock must be provided to converts the SXGA input image to digital data. However, since the maximum sampling clock the XGA monitor can support is 100 MHz, it will not be able to display the image data. Instead, the OSD generator 6 will generate an OSD message xe2x80x9cOut of Rangexe2x80x9d and display the OSD message on the LCD module 7.
The problems of the monitor based on the prior art technology due to its limitations and disadvantages are as follows. First, in a case where the resolution set in a CRT monitor is not supported by an LCD monitor when it is desired to use the LCD monitor instead of the CRT monitor, the image data will not be able to be displayed properly on the LCD monitor. It will simply display an OSD message xe2x80x9cOut of Rangexe2x80x9d on the screen of the LCD monitor. Second, in order to display the image data on the LCD monitor, the user must reconnect to the original CRT monitor, change the resolution of the image data so that the LCD monitor can support it, and connect to the LCD monitor. This will give a significant inconvenience to a user. Third, the user sometimes will regard this problem as a defect of the LCD monitor and will request to the service center for a repair.
Accordingly, the present invention is directed to an apparatus for processing input image signals in a monitor system having an LCD module that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an apparatus for processing the input image signals in a display system in order to view input images on the display system even when the monitor (LCD) system-does not support the resolution of the input images.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an apparatus for processing image signals in a monitor system having an LCD module includes an A/D converter converting analog R/G/B input image signals received into first 8-bit digital R/G/B image signals; and a microprocessor determining whether a resolution of the input image signals is supported by the LCD module and generating a corresponding control signal, the resolution being determined based on a horizontal/vertical sync signal received.
It further includes an image converter converting the first 8-bit digital R/G/B image signals into second 8-bit digital R/G/B image signals based on the control signal if the resolution of the input signals is not supported by the LCD module, the second 8-bit digital R/G/B image signals being displayable on the LCD module; a scaler adjusting frame sizes of the first or second 8-bit digital R/G/B image signals; and a switch outputting the first 8-bit digital R/G/B image signals to the scaler or the image converter depending on the control signal.
The image converter included in the apparatus described above includes a first sub-converter separately compressing the first 8-bit digital R/G/B image signals into Nbit digital R/G/B image signals, N being less than 8; a mixer mixing the N-bit digital R/G/B image signals to generate a N-bit mixed signal; a storage storing the N-bit mixed signal; and a second sub-converter extracting the stored N-bit mixed signal into the second 8-bit digital R/G/B image signals according to the control signal and separately outputting the second 8-bit digital R/G/B image signals to the scaler.
In another aspect of the present invention, an apparatus for processing image signals in a monitor system having an LCD module includes an A/D converter converting analog R/G/B input image signals received into first 8-bit digital R/G/B image signals; and a microprocessor determining whether a resolution of the input image signals is supported by the LCD module and generating a corresponding control signal, the resolution being determined using a horizontal/vertical sync signal received.
It further includes an image converter converting one of the first 8-bit digital R/G/B image signals into a second 8-bit digital image signal based on the control signal if the resolution of the input signals is not supported by the LCD module, the second 8-bit digital image signal being displayable on the LCD module; a scaler adjusting frame sizes of the first 8-bit digital R/G/B image signals or the second 8-bit digital image signal; and a switch outputting the one of the first 8-bit digital R/G/B image signals to the image converter or outputting all of the first 8-bit digital R/G/B image signals to scaler depending on the control signal.
Similarly, the image converter includes a first subconverter compressing the one of the first 8-bit digital R/G/B image signals into a N-bit digital image signal, where N is less then 8; a storage storing the n bit digital image signal; and a second sub-converter extracting the stored n bit digital image signal to generate the second 8-bit digital image signal based on the control signal and outputting the second 8-bit digital image signal to the scaler.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.